Green Screen on a budget
 

Hi folks,

This is a continuation of a thread in another section of these boards but is more light specific.
I've just read through several pages on here (and other sites) discussing worklights as a cheap option for setting up a light rig.
I have to get this set up over the weekend so I can present tests (at least) of green screen footage.
After just about managing to self build a green screen (from conduit/accessories and a sheet of green cotton) I now have to pay attention to lighting this.
Having had a look through local hardware stores I can see a couple of cheap options:

*500w halogens on tripod (perhaps not as high as one would like) - would 1 as a fill suffice?

*150w halogens (w/o tripods) - I thought perhaps these lower rated lights could be used to light the green screen (which I'm led to believe you shouldn't light too much?)

*halogens clamps

*flourescent worklights - approximate to 250w.

I may have scanned through one or two posts too quickly but might it be possible to replace the halogen bulbs with CFL bulbs...or does it take a few more adjustments than simply that?

For diffusing I thought of creating a frame with muslin/cotton sheeting stapled to it (either a door frame made from light timber or something smaller....I assume anything to close to the halogens at least will smolder in no time!).
I'll be testing in my living room - not sure whether halogens in the ceiling can be used as some kind of back light/rim light or to direct green spill downwards rather than on the subject:

http://farm3.static.flickr.com/2237/...372b41.jpg?v=0

Then of course there's the possibility of creating barn doors from card (I like the pre made barn doors posted on here but I need to be set up by the morning) and afixing gels to the kit (magenta for any back lights should I manage to set any up).

Here's a link to pretty much everything I can obtain from local hardware stores in the uk (I can't see an appropriate scoop solution)


http://www.wickes.co.uk/bin/venda?ex...archsubmit.y=0

Forgive me for my lack of experience on this, hopefully if this jobs comes off I can invest in a more pro set up.

Any advice will be most appreciated...I'll be onto these stores later today/early morning.

Many thanks.

What are you planning that you need softboxes for the size of doorways?

Basically 'on a budget' your only concerns are:
- A background in basically any contrasting color (or even black or white)
- Minimizing (color) spills

Making sure the background is even and evenly lit makes for much better keys. Get it as best you can. Use any lights you think will do the job!
Do not mix color temperatures for lighting the talent.

The goal of the 'greenscreen' is not to get a good key but to get a believable composite. Getting a good, clean key is nice as it saves you time and makes it easier to create a believable scene.

When you can't get the best screen possible, it will just take more time to clean up. Some software keyers can do a better job than others, saving you time.

A smaller FoV is easier to light evenly. If you're building a huge set, you'll have more challenges.

George/

This will be footage of a subject just talking to the camera. Eventually the background (for these jobs at least) will be white (a la apple adverts...although obviously not with the equipment I'm guessing it takes to make those commercials).
I'm doing a series of tests in my living room at the moment and it it comes off 'ok' then I guess the budget will be increased (via a series of jobs) giving scope for more pro equipment (and no doubt a larger studio space).
This will mostly end up on a web page rather than for a DVD.

My only concern now is the lights (the door frame idea came from the shower curtain on a pole to diffuse light from these halogen 500watters).

At this point I'm hesitating over grabbing one or two 500w tripod haolgens (for key and fill) and a couple of 150w for the screen...back fill I could perhaps use another 150w on a clamp behind the subject.
...then there's the question over could I swap out the 500w bulbs with CFL's which would no doubt be half as bright but a lot cooler and efficient...then of course I get into mixing colour temps and use of gels!
Hope I'm making sense?!?

It's a warm day (we get them occasionally in blighty :) ) and I'm anxious to pick up a set either this evening or on the morrow - the test footage has to be with the client at the beginning of next week.


Cheers.

My favorite budget screen lighting approach involves 2 5-gal buckets, 1 or two sacks of concrete, 2 8' pieces of electrical conduit, 4 u-bolts, and 2 2-bulb 4' shop light fluorescent fixtures with electronic ballasts, lamped with high-cri bulbs, everything from a home-hardware superstore.

Lessee', the concrete is mixed and into the buckets, stick in the conduit and harden. That's the stand. The fixtures get u-bolted onto the conduit. Easy.

Yes, you must have two fixtures for screen light. Even-ness is everything here. The 4' fluorescents are your friend here.

Yes, you must have backlight. It can be extremely difficult to cut the key without it. Magenta is a nice touch on the backlights, but having some distance between the subject and the screen helps more.

I've seen more conduit this week than I'd seen in my whole life!

Do you have a link to the fluorescent lights you are referring to (or should I step out of the 'worklight' jurisdiction and pop over to the kitchen lighting section? Not sure if I've seen those in my local searches - they stock the halogen's to the hilt though.
There's this type:

http://www.wickes.co.uk/invt/187109

giving approx 260w of lights but there 4 times the cost of the halogens...
Given I'm lighting both the subject and the screen and wouldn't really want to mix CRI's and Halogens if possible (colour temp).
I'm popping out in a bit to take a quick look at the options...

Many thanks.

No, what you want is more like this:

http://www.wickes.co.uk/Fluorescent-...ng/invt/162285

Except go for the 4 foot tube T8 model and make sure it has an electronic ballast. Typically in most Home Depot type places they will have some commercial 4 foot ceiling type fixtures. Maybe like ones used in a kitchen or office. Shoplights are fine too. The 2 and 4 bulb ones are what I am thinking of. I've shown this before but one of my customers did a DIY screen setup for less than $2500 USD using these type lights and some Cool Light 6x55 studio flo models for talent lighting where more control might be needed.

http://www.coollights.biz/wordpress/...tegory/gallery

He used the "linoleum" method for making the screen and it looks terrific. Several rows of shoplights overhead and aimed down at 45 degree angle. 4 foot daylight tubes used all over.

Using a cracked ice or prismatic diffusion panel over the fixtures will yield an even smoother lighting on the screen without cutting much light.

When doing greenscreen, absolutely every little thing counts if you want to get a convincing composite. Do a test shot, create a quick composite and give it an honest evaluation. If it doesn't feel right, then something's wrong. And sometimes you'll have to think long and hard to get it right.

Here's a list of things to consider:

Lighting on the screen has to be even, and the purer the green, the better it is for the most part. Simple is better. I've seen some try to fix a badly lit setup by adding lights, only to make things worse. Want to fix a hot spot? Pull the light farther away.

Compositing or keying software makes a huge difference. I have Keylight and Primatte and, of the two, I find Primatte much more adaptable and controllable.

Edges count! Bad edges mean bad keys and are among the biggest giveaways when it comes to composited scenes. Getting good edges requires using formats which have good color info. 4:2:2 is ideal. 4:2:0 works very well in HD. And 4:1:1 has to be the worst possible choice.

Is the lens clean? Does it create any sort of chromatic aberrations? Those aberrations can make it very difficult to control the quality of the edges.

You don't need a backlight if you have good keying software, use the right codec/format and work carefully. In fact, the backlight could spoil the overall effect, especially if there's nothing in the scene to warrant light coming from that direction.

Lighting is extremely important. Where is the light coming from? Hard light? Soft light? Do the shadows make sense compared to the background? Are the highlights right? Any reflections?

As a kid I recall seeing Bonanza and the studio-shots simulating outdoor scenes didn't make sense. There were too many shadows heading in different directions. So be aware that even a 10-year-old can spot a bad composite.

And when you do assemble the composite, you need to match the color of the light hitting your subject to the color of the background. And here's a very important tip that I'm hesitant to give away, only because it took a lot of thinking to get it right: It's not just the color of the light hitting your talent. Take note of the color of the light filling the shadows, too.

Here's something I did recently. Shot with the Sony EX1. I made the mistake of setting a negative value for "crispening" and should have left it at zero.

http://www.hawaiigoesfishing.com/vid...een_sample.mov

David,

You've got a wealth of information here. I'll add my 2 cents...

The fluoro lights Richard suggested I think are your best option for now. Halogen worklights are just too risky and hot in most situations. They'll work, but the fluorescent route will get you further.

That being said though, it's hard to get a good backlight with a fluorescent light so you'll want something with a little punch.

You could very easily use (2) of the 2 bank fluoro shop lights. If you're using any worklights, and you're not color correcting them, I'd suggest using a tungsten balanced fluorescent bulb so your lighting matches. This keeps the green screen from relflecting back the blue of the daylight balanced bulbs. Shoplights with bulbs here are about $20 for the each light plus bulbs. Pretty cheap. Not only that, you can swap out bulbs and keep using them. They're very handy, provide nice soft light for your green screen and run very cool, which is critical in small rooms.

I'd recommend a third bank for your keylight if you want to go that way. Again, very soft, even light. Use a piece of foamcore to bounce your fill into your talent.

Now.. if you're needing to match to a background, say like Dean showed (nice example, Dean!) you may want harder light (match the sun for example) which the fluoros won't give you. If you're going for generic lighting to throw in any background, I'd stick with softer light.

The 150 watt shop light I would use as your kicker / backlight.

Also - get your talent as far away from your background as possible. This prevents spill which your cotton fabric will give you. The magenta gel is good in certain circumstances if you're using a less robust NLE keyer but in most cases any third party keyer will have sufficient spill suppression and I know a number of VFX guys now who have sworn off the magenta / minus green gel solution due to the issues is gives when they're matching background and light wrapping with the software. Even in Sony Vegas, I've got a good spill suppression technique and do not use Magenta gels on my backlight.

What camera are you using? Makes a big difference as well like Dean pointed out. Most cameras, even prosumer cams have a zebra setting in them - turn this on and light according to it. You want about one or two stops from no zebras to full zebras - set at 70 - 75 ire and you'll get a nice bright green to key.

like I said, I'm only trying to add to the pot of goodness here.. lots of great suggestions.

mike

BTW: The setup I used had three lights. Two Lowel Tota Lights on the background (eefx.com green screen fabric) and one 500 watt Tota Light on the talent to simulate hard sunlight. Not flattering lighting at all, but realistic enough.

Thanks, Dean.

That reminds me, David. In Dean's case he used two of his three lights on the background. For interactive lighting, you could light your talent with a candle for what it's worth, but if the background isn't evenly and properly lit, it won't matter how you light your subject.

In Dean's case, he had one key light, up and to the subject's left to match the sunlight direction in the background place. Notice though he got some fill out of it as well, not just the direct sunlight. More akin to actual sunlight and yes, while not flattering, it's very real.

Again, if you light your background separately and correctly, you can do anything you want with your talent.

I'll also second the eefx green screen. Absolute best I've ever used.

mike

Huge thanks to you all for posting this advice.

I perhaps should've posted the link to my original thread in the JVC boards -
However to summarise:

I'm shooting on an extremely tight budget (the mention of $2500 is completely beyond me at this moment!) - this is for a test - if it comes off ok (and I've explained this to the client) there's scope (either through payment for the jobs or the company themselves will buy the kit in) for a more pro set up.

*Shooting 720p25 via the JVC HD100

*Editing/keying in either FCP or Motion 2 (which contains Primatte RT)

*For this project the client will eventually require a white background (although they may of course change their minds - the advice on lighting for a more realistic effect is invaluable - Dean's example is fantastic).
TBH - I've played around with stills in images, cutting out subjects to place on other backgrounds adhering to the concept of the light matching etc.

*I built a frame from plastic conduit and made a 'green screen' from the most natural green cotton material I could find.

*I'm having to shoot this is my living room with the screen facing a window.

With this in mind (and I have to make a choice on these lights by later today latest as the client would like to see footage on Monday!) might I be along the right lines with the following:

Two four foot (twin?) fluorescent shop lights for the background (will I need large gels to balance the daylight/match the tungsten, if I were to use a halogen worklight?)

Excuse my lack of experience but I'm still not sure what I would now use for the fill/key - was originally going to use a 500w halogen but a: I'll be mixing colour temps and b: sounds like these might be overkill?

I appreciate this is the weekend and you guys are quite a few hours behind the uk, but if anyone is around to advise me through the home straight (I feel I'm almost there!!) I'd be hugely grateful.

Cheers.

...just to add:

If I manage to source the 4 foot twin lights (with diffuser and electronic ballasts) - noted also that the majority of these are hardwired (adding to a lighting ring), so is it possible to add a mains plug?? - might this 260w equivalent fluorescent light be good for a key fill or could I light the subject with the aforementioned halogens (bounced/reflected and either the 150w or the 500w).

http://www.wickes.co.uk/invt/187109

Cheers.

David,

In trolling my fav royalty free lib I noticed that Digital Juice had a new (PDF) magazine out. It features a "how did we do it" for the "Tech Know" series, which should be somewhat close to the look you're striving for with the white background.

It may be a good read: http://www.digitaljuice.com/magazine/default.asp

George/

Hey thanks George - I'll take a gander at that shortly. Cheers for the linkie.

Quick update - I found twin 4 foot fluorescent tubes (hard wired - I'll have to rewire them for mains supply) but the physical store themselves hadn't any in :( I'll have to rush around in the morning (sods law in that all stores in the region are either out of stock or extremely low).

http://www.diy.com/diy/jsp/bq/nav/na...&isSearch=true

seem to be the one's referred to - 4 foot. Although I'd have to fix up some DIY stands for them.

Whilst at another store I found this:

http://www.screwfix.com/prods/49932/...KLIGHT-_-49932

which may come in handy as a fill...possible key...it's pretty bright but nothing like the 500w halogen would give. Still toying with the idea of getting a 150w halogen worklight as a key, but I'll trial this tomorrow morning.
Surprised that having a back light or not having one has split opinions, hopefully when I play with Primatte I'll get away with not having one.
Cheers.

Not necessary to gel these to match your subject lighting. Green is green for the most part and daylight color temp is IMHO better for getting a truer green. You'll white balance to the subject / foreground lighting hopefully with the green screen lighting turned off. Then after white balance, turn the screen lighting back on and you're ready to go.

Cheers Richard. I guess then it's a case of not mismatching colour temps on the green screen itself but as your lighting the screen and subject separately this will not matter.
The fluorescent tripod worklight I purchased might be handy as a fill but on quick tests last night not so good as a 'directional' key. Still toying with trying one of the cheaper halogens for this purpose, keeping the (when I pick them up) flori twin tubes for the screen itself. I probably sound panicky and anxious here but such is the fast turnaround (and never having done this before) that I can't help it...forgive me!

Thanks alot all.

Actually, you need to light and white balance for the green screen. That green has to be green. Not tinged with yellow, magenta or blue. The foreground can be lit with anything, as long as it's not spilling on the green screen.

If you're doing full-body work, then you'll have to light for the green environment and do any color grading in post. Some Hollywood productions use partial sets, with realistic floors or ground surfaces surrounded by green screen environments. http://www.studiodaily.com/main/casestudies/6503.html

Chroma key is, by definition, keying with color. So having a unique background that's different from anything else in the frame is the "key" -- pun somewhat unintended.

Primatte can pull some amazing keys in trying conditions -- I did it with a guy who happened to wear a green shirt -- but give yourself the best chance of doing it well and get that green screen as close to perfect as practically possible.

A hairlight will seperate your subject from the background and that is what you often want, however when you are compositing your main goal is to match the lighting in the background.

As you intend to use a white background, using a hairlight will, imho, be nessesary to prevent the finished product from looking 'flat'.

George/

P.S. Haven't you shot anything yet?

Just a thought: If this is a shot that's absolutely going to end up with a white background, then why not just shoot with a white background?

Light the white backdrop to get around 90 to 95 IRE, then light the talent seperately. Similar principals to lighting for green screen, but the goal is to get a nice bright white behind the talent.

All lights will have to match in terms of color temperature and spectral distribution.

And, yes, a hair light will give that needed sparkle to keep it from appearing drab.

Shooting against green to get a white background is a complicated approach to a simple problem. I should have read the original post more carefully.

Hi Dean,

This looks confusing. You must correctly light 1) the bg and 2) the talent.

Sure you must get an even bg without hotspots (near the subject), but whitebalancing for the bg lighting is not correct, especially if you're using different, uncoordinated lightsources for lighting the talent.

You should whitebalance to the talent. It is much easier in post and the bg color is far less important, especially with a good keyer.

Spill is more of a problem when the bg color spills onto the talent, which can be tricky to get rid of although 'modern' keyers have good spill supression. If foregroung lighting spills onto the background, you get hotspots; always good to avoid those as well.

George/

Over the past few years I learned (the hard way) that the background is critically important in getting the best possible key. That's where I see a lot of guys end up struggling in post. While you sometimes can get by with a badly lit background, there's always a lot less pain and suffering if it's correctly and evenly lit.

A badly exposed background can force a compositor to resort to masking several layers with different keys to deal with problem areas, or even having to rotoscope fingers.

I've done my share of rescuing bad green screen and invariably it's because the shot wasn't planned or executed properly. In one case it was a guy who wanted a certain pastel look, and programmed that in-camera. Tough key because there was seldom enough good chroma data for the keyer to lock-in upon.

Another time a director asked to warm up the shot in-camera to compensate for pale skin tone. I told him we'd do that in post -- the scene had to be kept "straight" to ensure a good key off the background. Warming it up would skew the green and possibly make it tough for any keyer to do the best possible job.

You're right about lighting the foreground properly. In fact, ideally everything should be carefully lit using matched sources. Mixing fluorescents with halogens and HMI's will create a nasty mess of odd highlights and contaminated shadows.

Still, if someone wanted to put the talent under some dramatic gelled lights, that's not a problem. At least as long as they're not actually seen standing on the green field itself.

I'm in the process of doing a small job where some footage shot with a Red One was delivered here, and neither Primatte nor Keylight could do a good job of it. The shot was extracted from the raw source undersaturated. The green in some parts were almost grey. Blue objects couldn't be separated from the green screen, and that's unusual for a keyer like Primatte.

I re-acquired the footage from the Red Raw source, and gave it a normal amount of saturation. It made a world of difference. Having a good green channel gives the keyer the best chance of extracting a clean key. And if the director wants to desaturate the scene or heavily grade it, he can do it after the key is extracted.

But first, it is vitally important to get a good chroma value in-camera. Trying to achieve a given chroma value after the fact in post is never as effective. An extreme example would be shooting green screen with black-and-white film. No post-production process will ever get that green value into the image.

It's a similar principal when trying to fix a skewed green in post. While the green might end up in the right place with enough tweaking, the relative values of the rest of the scene could get pulled right along with it. And soon fine details like hair disappear, translucent objects become transparent, and smooth edges turn rough.

Sometimes 15 minutes spent doing it exactly right in the studio will save 15 hours of trying to get it right in After Effects. This is a lesson I learned the hard way.

I haven't as yet...but I will be later on today. My main concern was getting a light set up on an extremely restricted budget, and not getting the incorrect mix of lights. As it turned out the lights Richard and others have mentioned (flori twin 4 footers) have been out of stock virtually everywhere in my local region. I have just found another store which states they are in stock so I'm nipping there shortly.

The light I did pick up (flori on a tripod) seems good for a fill, but less so for a key and I'm worried that it will spill onto the screen (unless I can 'park' it to the left/right of the subject and miss out the screen.
The other option was to use either a 150w or 500w halogen worklight for the fill/key - but confused over whether mixing lights temp is ok (bearing in mind you treat the bg and fg separately).

Those flori's always look a little cold to me...perfect for 'post modern russian sci fi' flicks...or is it just me?

Cheers.

I guess that answers my question about mixing lights!

Just worried I wont get a decent key with the flori's...in the ideal world have a direction arri key would be fantastic but that's not currently possible. I suppose I could create a barn for the tripod flori (or purchase one of Richard's). Good thing about these I suppose is the lack of heat.

How does this set up sound?:

left and right for green screen - 2 x twin 4' flori tubes with diffusers.

flori on tripod (possibly with mocked up barn door).

flori on clamp/tripod for back light?

Go with white balancing the subject rather than the screen?

Cheers...it's been a wonderful crash course over the past couple of days...hopefully I can apply the knowledge fairly successfully in the physical realm today.

OK folks...

couple of pics from the set up, whilst my camera warms up.

For the most part the screen is flat and evenly lit (had to 'rope' the sides to pull the cotton tight) only a slight issue over the top fifth starts to darken a little, but as the 'subject' in the test will be sat down this more than likely won't be seen by the cam (it looks a lot worse on the digi camera shots by the way). This is due to the Flori 4' lights not being high enough up but until I can find (or build) a tripod I'll have to use people sat down or small people (such as my daughters :) ).
I could've perhaps done with grabbing higher rated tubes - they came with 36w inside but can take up to 58w.
The subject will be around 5' from the screen and lit by the flori tripod (from their left and virtually no spill onto the green screen.

So here's my first attempt a setting up...hardly kinoflo in hollywood (see third attachment) but hopefully I can get something out of it...

http://farm3.static.flickr.com/2283/...acfd57.jpg?v=0

http://farm3.static.flickr.com/2248/...19785d.jpg?v=0

http://www.kinoflo.com/Image%20Gif/P...0Screen/1a.gif

Comments, as always, most welcome....now to start a test shot...

David, you may or may not need to "barn door" your screen lights off the subject. See what it looks like.

If you do need to, you can probably mask all you want with some duct/gaffers tape, cardboard, and aluminum foil.

Do test your key through a trial composite before shooting something that matters.

It was fairly hard for my [untrained] eye to gather whether light from this tripod flori was spilling directly onto the screen or whether this was a small amount of light bounced back from walls/ceiling. It was very limited, but I made up a cardboard 'barn door' anyway.

See here (suppress the giggles at the back!):

http://farm3.static.flickr.com/2218/...4dfb24.jpg?v=0

I think for further tests I'll add 4 x 58w (instead of 36w) for the screen.
I don't suppose you can purchase tungsten and/or daylight balanced tubes for the shop lights (as with kinoflo)? I guess that's asking too much of them isn't it?
I may also add a further tripod flori (energy saving type) as a backlight.
Met with the client today but that was to discuss another job...I'll be attempting the keying later today.
Cheers.

Sorry, on the run this morning but will look at pix later. A little spill is OK. I was concerned about screen lights spilling on subject. But that may be ok too, depending on color temp.

Here in the colonies, "warm white" is usually approximately tungsten. "Cool white" is usually aproximately daylight. If you go to the bulb manufacturer's web site you can find actual color temps and cri.

^^ I don't think the screen lights were spilling to be fair. The 'subject' was about 5 foot away and the bulbs at 36w (x4) aren't that bright. When I pick up some higher watted types I may think of building some kind of shade for tube lights (like you see with the kinoflo's).

Thanks Seth.

David,

What Fluoro light are you using for your key?

mike

This 'beautiful' beast...it's the only one I could find to match the fluori tube/shop lights without resorting to halogen. Adhering to my blinkin tight budget I've used this as both fill and key:

http://www.screwfix.co.uk/prods/4993...gle-Tripod-42W

Couple of frame grabs since capturing some test footage:

The first pic shows a frame before any keying had taken place - the tripod flori worked quite well (please feel free to tell me otherwise!). Perhaps may need to increase the wattage of the tube lights from 36w (x4) to something a little higher (although I'm aware that the screen shouldn't be lit too brightly) and I'll need to raise them higher on some sort of tripod (the zebra was fairly consistent up to the top 1/5 of the screen (where the light from the tubes fell off).
Could also perhaps sort out a few of the creases and maybe add a backlight (same type of light as the fill seeing as I have a flori only set up at the moment).

The second pic is my first key with motion (using Primatte RT, Blue & Green screen and Matt Choker) - slight concern over 'jaggies' which I hope are down to motion's lower rez view screen. I also found that some of the background (from a still/video) 'shone' through the hair occasionally!?!

The third pic is the key done in FCP - bit more long winded than Motion and seemed to get the image sharp, but I find there's an outline to the talent which isn't really acceptable for most backgrounds (bar the darker ones).

Appreciate you're all busy, but I literally have no one else in this environment in which to grab feedback.

Many thanks - you folks have really helped me get this far, where just a week ago I may have thought it impractical.

Cheers.

Those results aren't bad at all - your persistence is paying off, David.

Likely your Motion filter chain would benefit from a little chroma blur before the matt is cut - that should take care of jaggies.

Once again I am impressed with FCP's native filters - they really aren't bad for green screen work. I've had better results with "Chromakey" rather than "Green/Blue Screen".

Usually you'd want to use color bars as the background for key tests, as this will help reveal whether areas of the subject are keying (seeing background through the subject).

We've not really discussed your camera. If you have detail controls, you'll want to test with turning down detailing in the camera. This can help with the "outline" issue.

I think your screen lights are spilling substantially on the subject. You might experiment with barndooring off one of the screen lights - so you'd only get spill from one side. This has more to do with the look you like, but conventional thinking would be that side light from two sides connotes "studio shoot", from one side suggests more of a natural environment.

Thanks for that Seth. I'm fairly pleased with the results but want to push it till it's the best I can get it.

With the camera (JVC HD100) I tend to stick with Paulo Ciccone's Tru Colour 3 setting - that's another realm I've yet to seriously study (and I don't really have the monitoring equipment to pull off such probing). However I'll dig into the menu and turn the detailing down somewhat.

I'd set the lights quite close to the screen and a few feet away from the subject but I can where the spill is coming from now. I'm going to try and build some barn doors (a la kinoflo style) for these flori tubes - and good tip re the one side 'barned off' Seth, for the more natural look.
I may also use a backlight but this may not be necessary such are the keying results?

I didn't really use FCP's chroma keyer as much as Blue and Green Screen and Matt Choker - it's pretty good but I'm getting a pronounced outline and it looks 'cut out' rather than natural...trial and error for some time me thinks with both FCP and Motion :)

Massive thanks for the tips and advice once again.

I've found the FCP workflow to be pretty decent actually:

* create 8 point garbage matte

* colour smoothing

* chroma keyer

It little more complex than the Motion method, but until I try that again I can't confirm which I personally prefer/believe has the better 'engine' for the job.

I've found it tough to achieve near on perfection - the main 'spanner in the works' is the touch of green surrounding the hair (for the main). Despite the tools available to eliminate this (spill suppressor etc) it's more than likely down to spill from the screen or screen lights (despite my best intentions of separating both screen and subject). Will try flags for the tube lights (4' ones at that!) and pick up a back light to try too.
If I were to require a 'sunny/bright beach scene' might I run into problems mixing a halogen (for the subject) with the screen flori's if both were fairly isolated? Can't think of a bright enough fluorescent tubelight for this purpose.

have attached the latest FCP frame grabs: the whiteish scene works fairly well but seems a little 'effected' rather than natural...I guess I haven't the tools nor skill to carry out the apple advert effect just now.

the second pic is a bit of a mess around for a beach shot - the green palm tree behind the subject masks some of the small amounts of green spill in the hair. Certainly understand the concepts surrounding matching 'talent' with 'background'.

Anyway - thanks all - bit of a crash course for me and apologies for the persistent posts, but it's probably good source material for other posters wishing to pick up the techniques.

Cheers.

Not too shabby at all. Looks like you're getting good results to me.

David,

It's looks tons better - Couple of thoughts -

First of all, how are you measuring light on the green screen? Eye? Zebras? -

I think you could open up your iris a bit and get that screen to pop a bit more - Not sure you need that much more light on it. But it could stand to be a tad brighter - if that isn't an option, (FCP is different, I'm using Vegas) boost just the green channel while looking at a Waveform, try to get the screen to at least 60 ire. Not necessary but worth a shot to get the screen to a good level. That should take care of having to garbage matte it - I've not had to matte it in either Vegas or After Effects after pumping the green up a bit.

Poor man's spill supression - Vegas doesn't have it so I use this method - take your green screen footage and duplicate the clip - turn on the mask on the second clip and use that as an alpha channel to your green screen clip - only the footage of Elise should show through - nothing else -

Then take the green screen clip and desaturate the green completely. This will turn the green fairly grey (spill supression does the same) - because you have the Alpha matte working for you now, the green doesn't matter.

Voila, spill supression if the FCP one isn't working.

Other than that, if you flipped the footage horizontally against that exterior background, your lighting would match up pretty darn well. Shirt lettering would be backwards but you can see how the lighting works with what you already have shot.

All in all, it's looking really good. Not bad for shop lights. ;)

I just found a Husky 300 - 350 watt equivalent light at Home Depot (USA) - pretty cool but a little steep for the price. I may pick one up anyway and play...

http://www.toolsnob.com/archives/200...tripod_f_1.php

mike

Thanks Richard - you'll see I found those 4 foot tubes in the end. I'm going to pick up some slightly higher rated ones (I think they go up to 48w) but they're pretty bright as they are. Not sure it's possible to choose tungsten balanced flori's with these shoplights - possible to procure them?
Also - I don't suppose you created flags for this type of shop light Richard? :)
I may order your flags for a halogen worklight should I go that route.
In fact, I might try a 150w halogen (they're quite cheap) as either a fill or backlight (or both) - just in case I needed the 'bright sunny day' shot. As long as I separate the screen from the subject it should turn out ok?

Zebra's - however checking my settings I had the zebra set at 85-95% - probably ok for the subject but I believe this should be lower (70%?) for the green?
The iris was set at around 2.8 i.e. only a couple of stops before it was fully open - the tubelights were set close to the screen but perhaps I should pick up some stronger bulbs (as I understood it, the screen shouldn't be overlit).

Yes - FCP has a still supression (not sure about Motion) but it's always good to try other methods - thanks for that workflow.

I'm pleased you feel the results are fairly decent - I'm quite happy with them but fine tuning is needed. It's a struggle to eliminate bits of green spill, mainly from the hair, and with further tweaking I'm seeing degradation of the talent image (noticed parts of the image 'fizzing' especially lettering on the t shirt).

Cheers.

I like it! Sounds like a great technique, I look forward to trying it.

David, you are getting in the zone! Yes, 65-70 on the screen is the right range, and you don't want it hotter because that leads to more spill.

Dealing with spill... get the subject further away from the screen (I know, you're in your living room, but this is how its done), reduce the size of the screen until it is just big enough, sometimes magenta backlight will help, and then post spill suppression. But subject-to-screen distance is primary.

On another subject, if you are looking for believable composites that will have your audience wondering whether the subject was actually on-location, matching the lighting setups is important. For example, if you were really using the palm trees shot as a bg, you'd want a hard light source high and to the right, some deeper shadows, add a fan occassionally to simulate island breezes, add some seashore sound efx and bird calls deep in the background...

OTOH, many times that we are using green-screen we're not so concerned with "realism", which does, after all, take substantially more work!

I should stop watching Heroes...trying to match the almost seamless blending of blue/green screen there but on my tin pot budget :)

I was thinking earlier actually (inspired by Dean's chromakey) whether a fan might add that extra edge of realism (obviously not on full whack constantly....perhaps I'll save that for the 'speedboat' shot).

OK - I'll nudge the zebra down (by the way 'detail' in the cam is set a Min anyhow). I can see part of the fun (why else would we rack our brains over this?) would be realistically matching the background e.g. the aforementioned fan/hard lighting/shadows - it is indeed falling into place.

I was pretty tight against the wall filming though I guess I can move the subject a foot or two forwards (or use larger premises should the tests convince the client!).
I've actually just got hold of a much larger green screen today (£5 for a king size cotton sheet - had to order it in, not quite the bed linen colour of choice).

I will get a backlight - I know some use one some don't but I'll need if for other projects (interviews) anyhow.

*I've probably asked this a million times...and I feel like cocoa the clown keep on asking, so sorry folks, but:

I'm thoroughly satisfied with 4' flori tubes (more so with a tripod & flags for them) but where I to require a harsher light (sunny scenarios) could I get away with either a 500w or 150w halogen for the subject whilst using the tubes? As for the backlight, I could purchase another tripod flori (with the energy efficient lamps so I'd match the fill/key) or use a halogen for the backlight i.e. something a little bit more punchy.

btw - For me personally, FCP seems far more pliable and contains dozens more parameters than Motion for chroma-keying.

Thanks once more.

It's possible but not highly likely. 3200K is pretty rare in 4 foot tubes. The closest you're likely to find commonly is 3500K and that might be close enough to work although you'll find that with the lower color temperatures, even the slightest changes are more noticeable than in the higher ranges of daylight and above.

I never created barndoors for them because they're just too big. A common type is either corrugated plastic. Something light and durable. Foam core is okay but is far less durable and more disposable. Eggcrates are the best though for controlling sidespill in any softlight including fluorescents. If you could find a shoplight with an eggcrate on it thats removable, that would be nice.